Stay-bolt.



'UNTTED STATES PATENT OFFICE.

ETHAN I. DODDS, OF CENTRAL VALLEY, NEVI YORK, ASSIGNOB TO KERNEB. MANUFAC- TUBING COMPANY, F PITTSBURGH, PENNSYLVANIA, A. CORPORATION OF PENN- SYLVANIA.

STAY-BOLT.

To'all whom 'it may concern.' l

Be -it known that I, ETHAN I. Dones, a citizen of the United States, and af resident of Central-Valley, Orange county, New York, have invented a newand useful Iniprovement in Stay-Bolts, of which the f ollowing is a full, clear,.and exact'description, reference being had to the accompanycation, in which- Figure 1 is a perspective view of the two bars-from which the bolt is formed. Fig. 2 is a side elevation showing the bars welded and upset at oneend. -'Fig. 3 is a view similar to Fig. 2 showing the blank after twisting: Fig. 4.- is a view similar to Fig. .3 showing'theblank after'the otherv end is u pset and #welded-and the lhead ortions milled or machined.- Fig. 5 is a side elevation of the finished article.: Fig. 6 is a cross s ection of the finished articleon the line VI--QVI of lvFig.` 5;

My invention'relates to the class of stay bolts, and is desi edA to provide an improved articleof t is character'which s hall erform 'functions' heretofore not attained in devices of this-kind. 'if' Inl making. my improved stay bolt, I preferably proceedf'as 4follows: I take less than four preferably -rolled bars `-of preferably stay bolt iron and' pile them together, and thenlocall heat one'end portion which is tobe-wel ed. Thesebars'when piled togetherive the desired cross section, and are'loca ly heatedin theple to approximately a sweating heat, when these ends hegln to unite. 'The end portion thus heated is localized so. thatthe intermediate portion of the bar between the heads will not be welded together. The Sile istlien withdrawnv and the heated en is simultaneously upset and welded by die-action. I preferablyfuse twobars 2, 2, of half-round section, which are piled together in the form shown in Fia. 1. Fig. 2 shows-the blank after one en has been upset and welded to form the' enlarged head 3'. This head is upset in dies, the cavity of which is larger than the head desired, preferably at' least by onesixteenthof an inch. This is to compensate ng drawings,';^formingpart'of this speci-- for the losses in scale when welding to Specication of Letters Ilatnt. I Ptented Decljl, 1914.

Application alec april a, 191s. serial No. 759,915.

degrees. -I'have found that it is necessary to twistthe 'bars through at least an angle of 90 degrees-in order to give-the stay bolt the desired A'tensile capacityA and resistance against V'unwinding' under tensile strains to whichv the stay bolt is subjected in service. After tliistwisting operation, the other end portions of the bars are locally heated in the same manner as theiirst end, andv are simultaneously upset'and welded inthe same manner as. the other head 3, which is also of larger diameter than; that finally desired. The heads are then turned oi or milled on their cylindrical surfaces to give' ythe desired diameter; The heads are then rovided with-screw: threads, and thethrea s on one head are a continuation of those on the other head.- That is, the threads on both heads are the same `4asthough thebolt had been made ofthe-same diameter throughout and continuouslythreaded from one end to the other,.and the intermediate end portion of the bar 'then turned olf to remove the threads. .The threaded heads are.l indicated at 'in Fig.y 5. Tell-tale holes-Stare then drilled longitudinallythrough one'or both f heads into each connecting bar section.

The advanta es of my .invention lie in the liexibility o the bolt to resist the strains on the sheets, while at the samelftime the bolt gives the necessary resistance to compression, tension and torsion strains, and garli be inserted as easily as the ordinary In service the bolt is subjected to vibrations and gyratory movements due to the movements of the two plates or sheets on the boiler which the bolts connect. Owing to the' twisting of the bars through at least 90 degrees,the points of greatest bending stress 4will-be shifted through these bars instead of beinglocalized near one end of the bolt. Consequently -the life of the bolt is greatly extended. Owing to the twisting of the bars through an angle of at least 90 degrees, the bar possesses the necessary resistance to tensile strains and also to torsion strains, both in applying the bolt and in service.

I have found that if four or more connecting bars are used between the heads, the bolt will not give the desired resistance to the strains to which it is subjected, and is also diicult to insert since after one head has been partly screwed into place and the screw threads on the other head begin to engage the other sheet, the torsion in applyingwill twist the bolt slightly and lock it, so that it cannot be properly inserted. With four or lnore connecting bars, furthermore, diiliculty would be experienced in threading, on account of the liability of the bar to twist and distort the threads, so that the threads on one head would not properly aline with the threads on the other head as is necessary in order to insert the bolt. Furthermore, after these bolts are inserted the slightly projecting head portions thereof are peened over or headed slightly, to retain them in place and make the joints tight, and this action would distort and injure a bolt having four or more connecting bars, since the size of the bolt is limited to certain established standards, and the cross section of the bars cannot, therefore, be increased. By using less than four bars, the size of the bars is suflicient to give the desired resistance to strains both in making, applying and in use, and at the same time the bars are sufiiciently large to properly contain the telltale holes. The size of the telltale holes is fixed by government standards, and consequently the bars must be of proper size to contain these holes, and also to meet certain requirements under test. These requirementsare all met by my improved stay bolt, wherein two bars are used. Furthermore, my stay bolt will respond to the hammer test,;giving the proper sound to indicate whether or not one of the bars has been broken, to even a greater de ree than will an ordinary rigid stay bolt. he boiler can therefore be more easily, quickly and accurately tested in this manner. Furthermore, by using two or three bars, these bars will remain together in piled formv during heatin where it would be more difficult to hol a greater number together during heating and inserting into the upsetting and welding dies.

It will be noted that the outer surface of the connecting bars is scale covered, thus giving a much better surface for resistin the action of water than where a machined surface is exposed. The natural skin portion formed on the bars durin their manufacture is not cut away or isturbed, and consequently the stay bolt is stronger on this account.

The bars may be made of any desired shape, but should be less than four in number, and should have fiat engaging surfaces where they contact with each other.

By the words approximately semicylindrical in my claims, I intend to cover any ba'r having a shape approximating the semicylindrical form. For example, the exterior surface of the bar may be made up of a succession of plane or curved surfaces which may be of any number, provided they form an approximate semicylinder. For instance, the bar may behalf hexagon or half octagon in shape; or'the -succeeding exterior faces may be slightly concaved. All such variations are intended to be covered in my claims.

Vithin the scope of my broader claims, the bars may be` twisted either before or after either or both heads are formed. The upsetting may be carried out either before or after welding the ends, and other changes may be made without departing from my invention.

By the word stay bolt in myclaims, I do not intend to limit the use of my bolt to boilers, but to cover its use in any desired connection where the bolt is subjected to vibrations.

v I do not claim herein the process of mak-f IM ing the bolt, as this will formithe subjec matter of another application.

The present application is a continuation, in part, of my application ,Serial No. 713,419, filed August 6, 1912.

I claim:

1. A stay bolt having solid integral end heads and a body portion, thelatter comprising two separate members inte ral with said heads and extending from hea to head, said members having adjacent faces which extend the full diameter of the body members and contact with each other', the body members being twisted at leastf90 degrees to give the bolt flexibility to resist strains due to relative movements of-ffthe plates which it connects while retaining suicient resistance for other strains, the heads being so threaded as to allow engagement with the threaded portions ofvsucc'e'ssive separate plates which the stay bolt is to connect; substantially as described.

2. A stay bolt comprising two se arate bars, each of approximately semi-cy indri- 1 rea;

cal form and having a flat engaging surface, the two symmetrical bars forming a cylinder, said bars bein twisted atjleast 90 to give the bolt fiexibi ity to resis'tfstrains due to relative lateral movements of the plates which it connects while retaining sufficient resistancefor other strains, saidbars having solid integral end heads so'threaded as to allow engagement with the threaded holes of successive separated plates which the stay bolt is to connect; substantially as described.

3. A stay bolt comprising two separate bars, each of approximately semi-cylindrical form and having a flat engaging surface, the'two symmetrical barsforming a cylinder, said bars being twistediat' least 90 to give the bolt flexibility tore'sist strains due to relative lateral movements of the plates which', it connects while retaining sufficientresistance for other strains, said bars havingsolid` integral end head'sso threaded as to alow .engagement with the thr'eaed 'n testimony whereof, I hate hereunto set holes of successive separated plates which my hand.

the stay bolt is to connect, at least oneAef A I. DODDS. the heads having a te1l-ta1e holeextending Vitsrlesses:v

, 5 into one of th bars; substantially as de- JESSE B, Hmm,

scribed. H; M. Cnam. 

